Internal combustion engines

ABSTRACT

In a twin V-cylinder motorcycle engine the two cylinders and their overhead subassemblies are duplicates of each other and shifted 180* with respect to each other. Their overhead camshafts are driven off opposite ends of the crankshaft by speed reduction drive means disposed along opposite sides of the engine.

[ 1 June 12, 1973 United States Patent 1 1 Wickman INTERNAL COMBUSTIONENGINES Hoffmann 11/1970 Syson..........

Inventor: Vernon C. Wickman, Milwaukee,

Wis.

Assignee: AMF Incorporated, White Plains,

123/55 R 123/55 vs 7/1910 123/55 v1= 3/1938 Harley..... 12/1960Dolza......

[22] Filed: Apr. 23, 1971 Primary ExaminerLaurence M. GoodridgeAssistant ExaminerCort R. Flint [21] Appl. No.: 136,872

Att0rneyGeorge W. Price and Walter Lewis [5 7] ABSTRACT In a twinV-cylinder motorcycle engine the two cylinders and their overheadsubassemblies are duplicates of each other and shifted 180 with respectto each other.

[52] US. 1213/9027, 123/55 R [51} Int. F021 l/00 [58] Field ofSearch.................... 123/65 VD, 57 B,

123/55 R, 55 A, 44 C, 90.27, 44 E, 75 B, DIG.

1, DIG. 6, 55, 75 B Their overhead camshafts are driven off oppositeends of the crankshaft by speed reduction drive means disposed alongopposite sides of the engine.

[56] References Cited UNITED STATES PATENTS 2,113,077 4/1938 123/55 v 1Claim, 3 Drawing Figures PATENIED 1 2 SHEIIDFB FIG. I

ATTORNEY INVINTOR. VERNON c. WICKMAN Jim 1 PAIENTEI] JUN I 2 I973 SHEEI2 0F 3 FIG. 2

INVENTOR.

VERNON C. W CKMAN BY 4 AT fORNEY PATENTED 3.738.338

SHEEI 3 0f 3 FIG. 3

INVENTOR. VERNON C. WIC MAN ATTORNEY INTERNAL COMBUSTION ENGINES Thisinvention relates to an improvement in internal combustion engines, andmore particularly, to an improvement in twin V-cylinder engines.

In the prior art, as exemplified by prior William S. Harley, U.S. Pat.No. 2,111,242 (1938), it has been common practice in a twin V-cylindermotorcycle engine to provide distinct front and rear cylinders and tooperate the valves off one end of the crankshaft by a set of four pusherrods located on one side of the engine. Although this engine is verysatisfactory, it requires many parts and is relatively high cost.

It is-an object of this invention to provide an improved low cost twinV-cylinder engine by simplifying the above described prior artmotorcycle engine.

Briefly, in the invention the cylinders and their overhead subassembliesare duplicates of each other. By using overhead valve camshafts androtating the cylinders and their overhead subassemblies 180 with respectto each other and driving the camshafts off opposite ends of thecrankshaft the cylinders and their overhead subassemblies can beinterchangeable one for the other. Thus, in the invention only onecylinder and overhead subassembly design is needed for the twincylinders.

The features of the invention which are believed to be novel are setforth with particularity in the appended claims. The invention itself,however, both as to its organization and operation, together withfurther objects and advantages thereof, may best be understood byreference to the following description taken in connection with theaccompanying drawings in which:

FIG. 1 is a broken away side elevation view of a twin V-cylindermotorcycle engine incorporating the invention;

FIG. 2 is a sectional view taken along the section line 2-2 of FIG. 1;and

FIG. 3 is a sectional view taken along the section line 3-3 of FIG. 1.

In the description only those parts are described which are necessary tounderstand the invention, and duplicate parts are assigned the samereference numerals.

Referring now particularly to the drawings, shown therein is acrankshaft casing having a pair of cylinders 1.1 mounted thereon.The'upper ends of cylinders 11 are closed by subassemblies l2.subassemblies 12 comprise castings l3. Castings provide inlets andexhausts l4 and 15 which are opened and closed respectively by valves 16and 17. The valves are biased to closed position by springs 18 and aremoved to open position by rocker arms 19. The rocker arms 19 are carriedon shafts 19' mounted in castings l3 and castings 13 are closed bycovers 13'.

The rocker arms 19 for each cylinder are operated by cams 20 and 21which are mounted on an overhead camshaft 22. Camshafts 22 are mountedin the castings 13. The camshafts 22 are operated off opposite sh'aftends 23 of the engine crank 24 in a manner to be described shortly.

The cylinders ll have pistons 25 which are connected to crank 24 byconnecting rods 26. The parts 27 are flywheels such as disclosed in thementioned Harley U.S. Pat. No. 2,111,242. They served as arms forconnecting the crank 24 with the crank shaft ends 23. That is to say,the parts 23, 27, 24, 27, 23 in effect comprise the engine crankshaftwhich is mounted for rotation in the casing 10.

The left hand camshaft 22 of FIG. 1, see also FIG. 2, has its driven endpositioned on the far side of the engine to be driven off the far end 23of the crankshaft. In the case of the right hand cylinder of FIG. 1, seealso FIG. 3, it and its overhead subassembly is an exact duplicate ofthe one on the left. However, it is shifted or rotated so as to positionthe driven end of its camshaft 22 on the near side of the engine so itcan be driven off the near end 23 of the crankshaft. In other words, thetwo cylinders together with their overhead subassemblies are shifted orrotated 180 with respect to each other relative the lengthwise axes ofthe cylinders.

The near side crankshaft to camshaft drive comprises a first pair ofsprocket wheels 28, 29 and chain 30 set and an interconnected secondpair of sprocket wheels 31, 32 and chain 33 set. The sprocket 28 ismounted on the crankshaft end 23 and the sprocket 32 on the camshaft 22,see FIG. 3. The sprockets 29 and 31 are on a shaft 34 mounted in thecase 10. The sprocket 28 is smaller than the sprocket 29 and with thechain 30 provides a speed reduction on the near side of the engine forthe right hand camshaft 22.

On the far side of the engine a shaft 34 and a pair of sprocket wheels31, 32 and chain. 33 set are provided as on the near side of the engine.However, the speed reduction means comprises a pair of gears 35 and 36on the shafts 23 and 34 instead of the first sprocket wheel chain set28, 29, 30. This is to achieve a change in rotation between the twocamshafts 22 when viewing FIG. 1, since they have been shifted 180 withrespect to each other for drive off opposite ends of the crankshaft. Thedirections of rotation of the two crankshaft to camshaft speed reductionand drive means are shown by appropriate arrows in FIG. 1.

It will now be seen that aside from the difference in the two speedreduction means 28, 29 and 35, 36 each half of the engine is aninterchangeable duplicate of the other. This simplification and partsreduction makes for a substantial reduction in the cost of the engine.

While there has been shown and described a particular embodiment of theinvention, it will be obvious to those skilled in the art that changesand modifications may be made without departing from the invention, andtherefore, it is intended by the appended claims to cover all suchchanges and modifications as fall within the true spirit and scope ofthe invention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. In an internal combustion engine having a crankshaft casing and apair of piston cylinders mounted thereon in V-shaped spatial arrangementwith respect to each other, the upper ends of said cylinders havingcylinder heads mounted thereon, said heads containing valves, rockerarms for operating said valves, and a camshaft for operating said arms,said casing having a crankshaft mounted therein and pistons in saidcylinders connected to said crankshaft by connecting rods, saidcylinders and their named parts being duplicates of each other and beingpositioned one behind the other but in- 180 rotated relationshipwithrespect to each other relative the lengthwise axes of the cylinderswhereby the corresponding ends of said camshafts are driven off oppositeends of said crankshaft, one of said camshafts being driven off one endof said crankshaft other reduced speed shaft and a sprocket wheel onsaid another reduced speed shaft connected by a chain to a sprocketwheel mounted on said other camshaft along the opposite side of saidengine, whereby the crankshaftto camshaft speed reduction and drivemeans for one of said cylinders is positioned along one side of saidengine and the crankshaft to camshaft speed reduction and drive meansfor the other of said cylinders is positioned along the opposite side ofsaid engine.

1. In an internal combustion engine having a crankshaft casing and apair of piston cylinders mounted thereon in V-shaped spatial arrangementwith respect to each other, the upper ends of said cylinders havingcylinder heads mounted thereon, said heads containing valves, rockerarms for operating said valves, and a camshaft for operating said arms,said casing having a crankshaft mounted therein and pistons in saidcylinders connected to said crankshaft by connecting rods, saidcylinders and their named parts being duplicates of each other and beingpositioned one behind the other but in 180* rotated relationship withrespect to each other relative the lengthwise axes of the cylinderswhereby the corresponding ends of said camshafts are driven off oppositeends of said crankshaft, one of said camshafts being driven off one endof said crankshaft by a sprocket wheel mounted on said crankshaft oneend and a chain extending therefrom to another sprocket wheel mounted ona reduced speed shaft and another sprocket wheel mounted on said reducedspeed shaft connected by another chain to another sprocket wheel mountedon said one camshaft along one side of said engine, and the other ofsaid camshafts being driven off the other end of said crankshaft by agear mounted on said crankshaft other end and another gear which isengaged therewith and mounted on another reduced speed shaft and asprocket wheel on said another reduced speed shaft connected by a chainto a sprocket wheel mounted on said other camshaft along the oppositeside of said engine, whereby the crankshaft to camshaft speed reductionand drive means for one of said cylinders is positioned along one sideof said engine and the crankshaft to camshaft speed reduction and drivemeans for the other of said cylinders is positioned along the oppositeside of said engine.